Means for preventing seizure of moving parts



' l R. FLANAGAN Augzz, 195o mms Fon PREVENTING' sEIzURE or#- uovING rPARTS Filed Aug. 11. -1943 l "UNITED, STAT s la'itentedl Aug. 22 1950 las PA'ni-:N'g OFFICE MEANS FOR PREVENTING SEIZURE 0F MOVING PARTS Robert Flanagan, Glen Rock, N. J., assigner to Bendix Aviation Corporation, Teterboro, N. J., a corporation of Delaware the operation thereof often causes extreme rises in` temperature tending to cause the rotor to ex- Application August 11, 1943, Serial No. 498,243 7 Claims. (Cl. 23o-141) only and I may make changes in detail, especially in matters of shape, size and arrangement of parts l within the principle of the invention to the yfull extent indicated by the broad and generalmeanpand resulting in seizure between the rotor side surfaces and the housing.'

It has therefore been an object of my invention to provide novel means for cutting, shaving, or

scraping the side surfaces of the rotor as the same expands in response to a rise in temperature, so as to thereby lessen the hazards of seizure.

Another object of my invention is to provide a novel cutter means and arrangement for lessening` the hazards of seizure in rotary blowers of the Roots type.

Another object of my invention is to provide a novel" cutter device readily adapted for mounting in a conventional Roots blower for preventing seizure at the sides of the rotor. y

yAnother object of my invention is to provide a novel cutter formed of tooled steel, which has been heat-treated in a manner well known in the art so as to'adapt the same for scraping and cutting suitable plastics, mild steels, aluminum and other soft metals which may be utilized to form the rotor of an air compressor.

Another object of my invention is to provide a novel plate having mounted thereon a plurality of cutter blades, and the plate arranged for mountsl ing on the inner surface of the end walls of a y plan view of Figure 3 taken along the line 4-4 l blower casing so that the cutter blades may shave 't the side end surfaces of the rotor blades of a conventional Roots type blower upon the expansion thereof.

Another object of my invention is to providea novel system and method for preventing seizure between the housing and rotor of a Roots type blower. l

Another object of my invention is'to provide a novel compact cutter plate of the type described `with the accompanying drawings; and the novel features thereof are pointed out in the appended claims. The disclosure, however, is illustrative of great eiciency in` comparison to its size and ings of the terms in which the appended claims are expressed. I d

Inl the accompanying drawings like characters of reference indicate like parts in theA several views lwherein:

Figure 1 is a part cut away, part sectional ele"- vation of a blower showing-my novel cutter plates in position within the housingof the blower.

Figure 2 is a sectional view of Figure 1 taken along the lines 2-2 and looking in the direction of the arrows.

Figure 3 is a plan view of my novel cutter plate,` together with an end view thereof.

Figure 4 fis an enlarged sectional view` of the and looking in the direction of the arrows.

Referring more particularly to the drawings,

it will be seen that in Figures 1 and 2 there is shown a conventional blower of the Roots type having a housing indicated generally by the numeral I. housing I' in any convenienbmanner.`

The housing I has provided inlet and outlet conduits 4 and 5. Rotatably mounted within the housing I are impeller rotors and 1. The rotor 6 hasfafiixed at oppositeI sides thereof shafts I and 9 which are journalled in suitable bearings provided in the end members 2 and 3, respectively.

Similarly, the rotor 1 has aiiixed at opposite sides oi the same shafts I0 and- I I, which are likewise journalled in suitable bea-rings provided in the end members 2 and 3, respectively. The shafts 8 and I0 have xed thereongpiloting gears I3 and I4 which in turn are operatively connected with a driving shaft I5.

The impeller rotors `6 and 'I have been shown of conventional type, each having three impeller teeth or lobes which intermesh in sealing relation in a manner well known in the art.

In order to further effectively seal the engagement of the impeller gear teeth with the housing and with each other, each tooth is provided at the end thereof with a suitable plastic or rubber seal indicated by the numeral I6. Theseal I8 projects slightly beyond the outside circumference of the gear tooth so as to engage in sealing relation the inner surface of the housing.- After.

the contact face of the seal I6 has worn away the same can be readily removed and a new seal inserted in its place.

,In operation of a pump of the End members 2 and 3 are adixed to the,l

type described the fluid medium, such as air, enters the pump housing I through the inlet 4 as indicated at Figure 2. As the rotors rotate in the direction of the arrows, the intake fluid is entrapped between the housing I and each two successive rotor teeth and carried around by the rotatingdntermeshing impeller rotors 8 and 1, and the fluid medium ejected from the outlet conduit 5 as indicated by the arrows.

During such operation the rapid rotation of the impeller rotors 6 and 1 causes a rise in temperature due to increased pressure of tlie fluid medium. Such rise in temperature in the conventional type Whatisclaimedis: 1. A Roots type blower having a housing.

' mutually interengaging impeller rotors mounted within said housing, cutter ailixed at the inner side surfaces of said housing and projecting inwardly into said housing for shaving adjacent side surfaces of said rotors upon expansion of the latter in such manner as to prevent seizure of said rotors between the inner .side surfaces of said housing upon an increase in temperature.

2. A Roots type blower having a housing, said housing having an inlet and an outlet opening for a fluid medium, a pair of mutually interengaging of. rotary pump often causes therotors to expand y and in spaced relation one to the other.`

The blades I8 are preferably formed of a tooled steel which has been heat-treated in a manner well known in the art so as to adapt the same for .rutting or shaving the surface of an adjacent rotary member formed of a softer material such as suitable plastics, mild steels, aluminum and other soft metals.

For convenience in mounting, the plate I1 has provided the attachment screws I9 and 20, whereby the plate I1 may be fastened at the inner surface of the opposite end members. 2 and 3 as shown in Figures 1 and 2.

Suitable recesses 2 I, as indicated in Figure 1. are provided in the inner surface of the end memimpeller rotors, rotary shafts for rotatably mounting said impeller rotors, within said housing, knife-like blade members positioned at opposite sides ofA each of 4said impeller rotors and projecting inwardly of the housing for engagement with the ends of the rotors, said knife-like blades extending substantially parallel to a plane extending through the centers of rotation of said shafts and positioned at that side of said plane nearest the inlet opening in said housing, whereby upon expansion of said rotors in response to a rise in temperature said impeller rotors on rotating will engagesaid blades at the longitudinal ends thereof and then move longitudinally and laterally in relation thereto so as to cause the removal of said expanded portion of said impeller rotors.

3. A device for reducing the hazard of seizure of moving parts, comprising, in combination, a plurality of moving parts, a housing for said moving parts, a circular plate mounted in the inner bers 2 and 3 for receiving the cutter plates I1.',

The cutter plates I1 are mounted within the housing I as best shown in Figure 2, at a point on the end member to that side of an imaginary line X-X drawn through the centers of rotation of the impeller rotors Band 1 nearest the inlet I.

rotor, seizure between such side of the rotor and v the inner surface of the end member maybe readily avoided. Moreover, it will be seen that the knife-like blades I8 areso positioned with respect to the rotors that the side of the rotor teeth in passing the-knife-like blades I8 first strikes the blades at the ends thereof and move longitudinally and laterally in respectthereto, so that the expanded portions of the rotor teeth are shaved therefrom with a combined cutting and scraping eiect for the more efllcient removal of such expanded portions of the rotor.

Thus it will be seen that I have provided simple and eflicient means for avoiding seizure in a rotary type blower due to extreme temperature increases during the operation thereof.

Although only one embodiment of the invention has been illustrated and described, various .changes in the form and relative arrangement of the parts, which will now appear to Vthose skilled in the art, may be made without departing from the scope of the invention. Reference is, therefore, to be had to the appended claims for a deflnition of the limits of the invention.

side surfaces of said housing, knife-like blades which, in one position of the device, extend vertically and project horizontally outwardly from said circular plates into the interior of said housing and positioned adjacent side surfaces of said moving parts, and said knife-like blades so arranged 'in relation to said moving parts that upon the expansion of said parts the side surfaces of said moving parts will engage said blades at the longitudinal ends thereof, and then move longitudinally and laterally inrelation to said blades for removing expanded structurally integral portions of said moving parts.

4. In a rotary blower of the type including a housing having an end wall, and a. vrotor journaled in` said housing and having an end surface adjacent a surface of said end wall, one of said adjacent surfaces having a hardness less than the hardness of the other of said adjacent surfaces, the other of said adjacent surfaces being provided with substantially sharp blade means aixed thereto and capable of rapidly abrading said one surface upon rotating contact relative thereto due to longitudinal thermal expansion of the rotor relative to the housing, whereby an optimum working clearance is maintained between said en d wall of the housing and said adjacent end surface of the rotor.

5. The combination defined by claim 4 wherein the means for abrading the surface comprises a plurality of spaced apart knife-like blades for shaving the adjacent surface of said one end wall upon expansion of said rotor due to an increase in temperature.

6. In a rotary blower ofthe type including a housing having an end wall, and a rotor journaled -in said housing and having an end surface adjacent a surface of said end wall, one of said adjacent surfaces being of a relatively soft material and arranged to present an abradable surface to `said other adjacent surface, said other adjacent surface being provided with substantially cutter members' capable of rapidly shaving said adjacent one surface upon rotating contact relative thereto, whereby an optimum working clearance is maintained between said end wall surface and said adjacent end surface of the rotor.

7. A rotary blower including a housirfg having an end wall, a rotor journaled in said housing and having an end surface adjacent a surface of said end wall, means to prevent seizure of said rotor by said end wall upon thermal expansion ofthe rotor, said means comprising one of said surfaces including cutter means afxed thereto and the other of said surfaces formed of a relatively readily abradable material such that, upon rotating contact ot the cutter means of said one surface with said other surface, the other surface is rapidly worn away by engagement with said cutter means to provide working clearance.

ROBERT FLANAGAN. n

REFERENCES CITED The following references are of record in the me of this patent:

STATES PATEN'IiS Numoer Name Date 247,691 vRoots Sept. 27, 1881 799,642 Frasch Sept. 19, 1905 lo 800,127 Frasch Sept. 19,- 1905 1,030,083 Green June 18, 1912 1,785,386 McIntyre Dec. 16, 1930 2,087,527 Norton July 20, 1937 FOREIGN. PATENTS 15 Number Country Date 464,475 Great Britain Apr. 16, 1937 Certificate of Correction" Patent No. 2,519,557 August 22, 1950 ROBERT FLANAGAN It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 4, line 4, after the Word cutter insert means;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 31st day of October, A. D. 1950.

[SEAL] THOMAS F. MURPHY,

Assistant ommz'sszoner of Patents. 

